This invention relates to a template generator and, in particular, to a template generator for use in a woodworking machine that utilizes a conventional router as a cutting means.
In U.S. Pat. No. 3,946,774, there is disclosed a woodworking machine that employs a carriage mounted router for cutting contoured surfaces of different designs in a work piece. For want of a better name, this device shall be herein referred to as a router turning machine. As disclosed in the noted patent, the work piece is supported in the work bed between a head stock and a tail stock so that it can be turned about the horizontal axis of the machine. The router, on the other hand, is vertically supported over the work upon a carriage with the cutter being generally perpendicularly aligned with the axis of the machine. The carriage is slidably mounted upon a horizontal guide rail to enable the tool to be moved parallel with the work along the length of the bed. The carriage is also pivotably supported upon the guide rail to allow the carriage to swing in a vertical plane about the rail and thus raise or lower the cutter in reference to the work. A pair of adjusting screws are provided by which the vertical positioning of the carriage may be regulated, thereby controlling the depth of cut taken by the tool.
Both the carriage and the work can be moved independently so that circular and axial cuts can be produced in the work. Through means of a pulley system, the turning motion of the work may also be coordinated with the axial motion of the carriage whereupon the cutter is able to generate a spiral groove in the work piece.
Although not disclosed in the noted patent, the vertical positioning of the carriage along the axial length of the work bed is also controllable by use of a template that is mounted adjacent to the bed. A follower is secured in the vertically movable side wall of the carriage and is arranged to ride in the contoured control surface of the template. a prescribed vertical motion is thus imparted to the cutter which causes the cutter to be raised and lowered in reference to the work as the carriage is moved axially along the length of the work bed.
The motion translated to the cutter by the follower system is arcuate in form because of the carriage mounting arrangement. The template profile must therefore be corrected in order to compensate for the non-linearity of the system. As a consequence, original or preexisting parts cannot be used as master templates from which exact duplicates can be generated. The templates that are available are limited to a few basic designs. This seriously impedes the usefulness of the machine as well as restricts the type of creative work that can be performed thereon.